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Research Collection School Of Computing and Information Systems

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Full-Text Articles in Databases and Information Systems

Ltam: A Location-Temporal Authorization Model, Hai Yu, Ee Peng Lim Aug 2004

Ltam: A Location-Temporal Authorization Model, Hai Yu, Ee Peng Lim

Research Collection School Of Computing and Information Systems

This paper describes an authorization model for specifying access privileges of users who make requests to access a set of locations in a building or more generally a physical or virtual infrastructure. In the model, primitive locations can be grouped into composite locations and the connectivities among locations are represented in a multilevel location graph. Authorizations are defined with temporal constraints on the time to enter and leave a location and constraints on the number of times users can access a location. Access control enforcement is conducted by monitoring user movement and checking access requests against an authorization database. The …

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Group-Based Relevance Feedback With Support Vector Machine Ensembles, Steven C. H. Hoi, Michael R. Lyu Aug 2004

Group-Based Relevance Feedback With Support Vector Machine Ensembles, Steven C. H. Hoi, Michael R. Lyu

Research Collection School Of Computing and Information Systems

Support vector machines (SVMs) have become one of the most promising techniques for relevance feedback in content-based image retrieval (CBIR). Typical SVM-based relevance feedback techniquessimply apply the strict binary classifications: positive (relevant) class and negative (irrelevant) class. However, in a real-world relevance feedback task, it is more reasonable and practical to assume the data come from multiple positive classes and one negative class. In order to formulate an effective relevance feedback algorithm, we propose a novel group-based relevance feedback scheme constructed with the SVM ensembles technique. Experiments are conducted to evaluate the performance of our proposed scheme and the traditional …

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High Accuracy Classification Of Eeg Signal, Wenjie Xu, Cuitai Guan, Chng Eng Siong, S. Ranganatha, Manoj Thulasidas, Jiankang Wu Aug 2004

High Accuracy Classification Of Eeg Signal, Wenjie Xu, Cuitai Guan, Chng Eng Siong, S. Ranganatha, Manoj Thulasidas, Jiankang Wu

Research Collection School Of Computing and Information Systems

Improving classification accuracy is a key issue to advancing brain computer interface (BCI) research from laboratory to real world applications. This article presents a high accuracy EEC signal classification method using single trial EEC signal to detect left and right finger movement. We apply an optimal temporal filter to remove irrelevant signal and subsequently extract key features from spatial patterns of EEG signal to perform classification. Specifically, the proposed method transforms the original EEG signal into a spatial pattern and applies the RBF feature selection method to generate robust feature. Classification is performed by the SVM and our experimental result …

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Gesture Tracking And Recognition For Lecture Video Editing, Feng Wang, Chong-Wah Ngo, Ting-Chuen Pong Aug 2004

Gesture Tracking And Recognition For Lecture Video Editing, Feng Wang, Chong-Wah Ngo, Ting-Chuen Pong

Research Collection School Of Computing and Information Systems

This paper presents a gesture based driven approach for video editing. Given a lecture video, we adopt novel approaches to automatically detect and synchronize its content with electronic slides. The gestures in each synchronized topic (or shot) are then tracked and recognized continuously. By registering shots and slides and recovering their transformation, the regions where the gestures take place can be known. Based on the recognized gestures and their registered positions, the information in slides can be seamlessly extracted, not only to assist video editing, but also to enhance the quality of original lecture video.

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Values Of Mobile Technology In Education, Fiona Fui-Hoon Nah, Keng Siau, H. Sheng Aug 2004

Values Of Mobile Technology In Education, Fiona Fui-Hoon Nah, Keng Siau, H. Sheng

Research Collection School Of Computing and Information Systems

Mobile technology shows promise in supporting and improving education and its delivery. Coupled with the use of mobile devices and software/hardware solutions that make it possible to access educational content, students can be exposed to new educational experience. Applications of mobile technology in education can provide many benefits including greater flexibility, more available education resources, as well as greater convenience, accessibility and responsiveness. As a new phenomenon that will be widely used and adopted in the years to come, the values of mobile technology in education should be better understood and researched. This research outlines our empirical study to examine …

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Investigating Deception In Cyberspace, Holtjona Galanxhi, Fiona Fui-Hoon Nah Aug 2004

Investigating Deception In Cyberspace, Holtjona Galanxhi, Fiona Fui-Hoon Nah

Research Collection School Of Computing and Information Systems

The use of anthropomorphic avatars provides Internet users the opportunity and freedom to present their desired identity. As cyberspace becomes a heaven for deceptive behavior, human-computer interaction research will need to be carried out to study and understand these deceptive behaviors. The objective of this research is to investigate the behavior of deceivers and truthtellers in the cyberspace environment and to examine how their intention to deceive may influence the choice of their avatars. The effect of using avatars to support communication will also be studied. This research provides insights on communication and trust issues in avatar environments.

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An Interactive Learning Environment For A Dynamic Educational Digital Library, Ee Peng Lim, Dion Hoe-Lian Goh, Yin-Leng Theng, Eng-Kai Suen Jul 2004

An Interactive Learning Environment For A Dynamic Educational Digital Library, Ee Peng Lim, Dion Hoe-Lian Goh, Yin-Leng Theng, Eng-Kai Suen

Research Collection School Of Computing and Information Systems

GeogDL is a digital library of geography examination resources designed to assist students in preparing for a national geography examination in Singapore. We describe an interactive learning environment built into GeogDL that consists of four major components. The practice and review module allows students to attempt individual examination questions, the mock exam provides a simulation of the actual geography examination, the trends analysis tool provides an overview of the types of questions asked in previous examinations, while the contributions module allows students and teachers to create and share knowledge within the digital library.

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Biased Support Vector Machine For Relevance Feedback In Image Retrieval, Steven Hoi, Chi-Hang Chan, Kaizhu Huang, Michael R. Lyu, Irwin King Jul 2004

Biased Support Vector Machine For Relevance Feedback In Image Retrieval, Steven Hoi, Chi-Hang Chan, Kaizhu Huang, Michael R. Lyu, Irwin King

Research Collection School Of Computing and Information Systems

Recently, support vector machines (SVMs) have been engaged on relevance feedback tasks in content-based image retrieval. Typical approaches by SVMs treat the relevance feedback as a strict binary classification problem. However, these approaches do not consider an important issue of relevance feedback, i.e. the unbalanced dataset problem, in which the negative instances largely outnumber the positive instances. For solving this problem, we propose a novel technique to formulate the relevance feedback based on a modified SVM called biased support vector machine (Biased SVM or BSVM). Mathematical formulation and explanations are provided for showing the advantages. Experiments are conducted to evaluate …

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A Support-Ordered Trie For Fast Frequent Itemset Discovery, Ee Peng Lim, Yew-Kwong Woon, Wee-Keong Ng Jul 2004

A Support-Ordered Trie For Fast Frequent Itemset Discovery, Ee Peng Lim, Yew-Kwong Woon, Wee-Keong Ng

Research Collection School Of Computing and Information Systems

The importance of data mining is apparent with the advent of powerful data collection and storage tools; raw data is so abundant that manual analysis is no longer possible. Unfortunately, data mining problems are difficult to solve and this prompted the introduction of several novel data structures to improve mining efficiency. Here, we critically examine existing preprocessing data structures used in association rule mining for enhancing performance in an attempt to understand their strengths and weaknesses. Our analyses culminate in a practical structure called the SOTrielT (support-ordered trie itemset) and two synergistic algorithms to accompany it for the fast discovery …

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An Empirical Investigation On End-Users’ Acceptance Of Enterprise Systems, Fiona Fui-Hoon Nah, Xin Tan, Soon Hing Teh Jul 2004

An Empirical Investigation On End-Users’ Acceptance Of Enterprise Systems, Fiona Fui-Hoon Nah, Xin Tan, Soon Hing Teh

Research Collection School Of Computing and Information Systems

Despite the huge investments by organizations in ERP implementation, maintenance, and user training, ERP implementation failures and less-than-satisfactory productivity improvements are common. End-users’ reluctance or unwillingness to adopt or use the newly implemented ERP system is often cited as one of the main reasons for ERP failures. To examine factors leading to the lack of end-user acceptance of ERP systems, we reviewed the literature on user adoption of IT in mandatory contexts, developed hypotheses to explain ERP user acceptance, and conducted a survey study to test the hypotheses. In particular, we examined end-users’ attitudes toward system use and symbolic adoption, …

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Proprietary And Open Systems Adoption In E-Procurement: A Risk-Augmented Transactions Cost Perspective, Robert J. Kauffman, Hamid Mohtadi Jun 2004

Proprietary And Open Systems Adoption In E-Procurement: A Risk-Augmented Transactions Cost Perspective, Robert J. Kauffman, Hamid Mohtadi

Research Collection School Of Computing and Information Systems

We present an economic model that enables the study of incentives for business-to-business (B2B) e-procurement systems investments that permit inventory coordination and improved operational control. We focus on the information technology adoption behavior of firms in the presence of transaction costs, agency costs and information uncertainty. We conclude that it is appropriate to rethink the prior theory and develop an extended transaction-cost theory perspective that incorporates the possibility of shocks. We distinguish among three kinds of B2B e-procurement systems platforms. Proprietary platform procurement systems involve traditional electronic data interchange (EDI) technologies. Open platform procurement systems are associated with e-market Web …

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Furthering The Understanding Of Practical Complexity: Identifying A Kernel Of Uml, J. Erickson, Keng Siau Jun 2004

Furthering The Understanding Of Practical Complexity: Identifying A Kernel Of Uml, J. Erickson, Keng Siau

Research Collection School Of Computing and Information Systems

The Unified Modeling Language (UML) was adopted by the Object Management Group as the standard visual modeling language for OO systems development. However, UML has been criticized in the literature for its complexity, inconsistent semantics, and ambiguous constructs. A set of complexity indices for UML in aggregate, and the nine diagramming techniques individually, was compiled recently. Since this set of metrics is based on inclusion of all possible constructs in UML, it thus provides an indication of the theoretical (maximum) complexity of the modeling methods. This paper contends that in practice, developers do not use all of the possible diagrams …

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Steganographic Schemes For File System And B-Tree, Hwee Hwa Pang, Kian-Lee Tan, Xuan Zhou Jun 2004

Steganographic Schemes For File System And B-Tree, Hwee Hwa Pang, Kian-Lee Tan, Xuan Zhou

Research Collection School Of Computing and Information Systems

While user access control and encryption can protect valuable data from passive observers, these techniques leave visible ciphertexts that are likely to alert an active adversary to the existence of the data. We introduce StegFD, a steganographic file driver that securely hides user-selected files in a file system so that, without the corresponding access keys, an attacker would not be able to deduce their existence. Unlike other steganographic schemes proposed previously, our construction satisfies the prerequisites of a practical file system in ensuring the integrity of the files and maintaining efficient space utilization. We also propose two schemes for implementing …

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The Complexity Of Uml: Differentiating Practical And Theoretical Complexity, J. Erickson, Keng Siau Jun 2004

The Complexity Of Uml: Differentiating Practical And Theoretical Complexity, J. Erickson, Keng Siau

Research Collection School Of Computing and Information Systems

UML (Unified Modeling Language) has been criticized for its complexity, relating to users, and those learning to use it. Using Rossi and Brinkkemper’s [9] complexity metrics, Siau and Cao [10] completed a complexity analysis of UML and 36 other modeling techniques, finding that UML is indeed more complex than other techniques. Siau, Erickson and Lee [11] argued that Rossi and Brinkkemper’s metrics present the theoretical maximum complexity, as opposed to a practitioner-based complexity, that must be less than the theoretical maximum. The current research proposes that a subset of UML (a kernel) composed of the most commonly used constructs, would …

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Web Image Learning For Searching Semantic Concepts In Image Databases, Steven Hoi, Michael R. Lyu May 2004

Web Image Learning For Searching Semantic Concepts In Image Databases, Steven Hoi, Michael R. Lyu

Research Collection School Of Computing and Information Systems

Without textual descriptions or label information of images, searching semantic concepts in image databases is still a very challenging task. While automatic annotation techniques are yet a long way off, we can seek other alternative techniques to solve this difficult issue. In this paper, we propose to learn Web images for searching the semantic concepts in large image databases. To formulate effective algorithms, we suggest to engage the support vector machines for attacking the problem. We evaluate our algorithm in a large image database and demonstrate the preliminary yet promising results.

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Modified Art 2a Growing Network Capable Of Generating A Fixed Number Of Nodes, Ji He, Ah-Hwee Tan, Chew-Lim Tan May 2004

Modified Art 2a Growing Network Capable Of Generating A Fixed Number Of Nodes, Ji He, Ah-Hwee Tan, Chew-Lim Tan

Research Collection School Of Computing and Information Systems

This paper introduces the Adaptive Resonance Theory under Constraint (ART-C 2A) learning paradigm based on ART 2A, which is capable of generating a user-defined number of recognition nodes through online estimation of an appropriate vigilance threshold. Empirical experiments compare the cluster validity and the learning efficiency of ART-C 2A with those of ART 2A, as well as three closely related clustering methods, namely online K-Means, batch K-Means, and SOM, in a quantitative manner. Besides retaining the online cluster creation capability of ART 2A, ART-C 2A gives the alternative clustering solution, which allows a direct control on the number of output …

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A Stage Model For E-Government Implementation, Keng Siau, Y. Long May 2004

A Stage Model For E-Government Implementation, Keng Siau, Y. Long

Research Collection School Of Computing and Information Systems

With the advancement of wired and wireless technologies in recent years, the concept of an e-government has attracted increasing interests from both researchers and practitioners. The E-Government Act of 2002 was signed into law by President Bush to encourage government agencies to efficiently and effectively serve their customers over the Web. E-government presents a way for government agencies to use new technologies, such as the Internet, to provide citizens, businesses, and other governments with a more convenient access to government information and services, to improve the quality of services, and to provide greater opportunities for citizens to participate in democratic …

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An Automated Algorithm For Extracting Website Skeleton, Zehua Liu, Wee-Keong Ng, Ee Peng Lim Mar 2004

An Automated Algorithm For Extracting Website Skeleton, Zehua Liu, Wee-Keong Ng, Ee Peng Lim

Research Collection School Of Computing and Information Systems

The huge amount of information available on the Web has attracted many research efforts into developing wrappers that extract data from webpages. However, as most of the systems for generating wrappers focus on extracting data at page-level, data extraction at site-level remains a manual or semi-automatic process. In this paper, we study the problem of extracting website skeleton, i.e. extracting the underlying hyperlink structure that is used to organize the content pages in a given website. We propose an automated algorithm, called the Sew algorithm, to discover the skeleton of a website. Given a page, the algorithm examines hyperlinks in …

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Authenticating Query Results In Edge Computing, Hwee Hwa Pang, Kian-Lee Tan Mar 2004

Authenticating Query Results In Edge Computing, Hwee Hwa Pang, Kian-Lee Tan

Research Collection School Of Computing and Information Systems

Edge computing pushes application logic and the underlying data to the edge of the network, with the aim of improving availability and scalability. As the edge servers are not necessarily secure, there must be provisions for validating their outputs. This paper proposes a mechanism that creates a verification object (VO) for checking the integrity of each query result produced by an edge server - that values in the result tuples are not tampered with, and that no spurious tuples are introduced. The primary advantages of our proposed mechanism are that the VO is independent of the database size, and that …

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Hiding Data Accesses In Steganographic File System, Xuan Zhou, Hwee Hwa Pang, Kian-Lee Tan Mar 2004

Hiding Data Accesses In Steganographic File System, Xuan Zhou, Hwee Hwa Pang, Kian-Lee Tan

Research Collection School Of Computing and Information Systems

To support ubiquitous computing, the underlying data have to be persistent and available anywhere-anytime. The data thus have to migrate from devices local to individual computers, to shared storage volumes that are accessible over open network. This potentially exposes the data to heightened security risks. We propose two mechanisms, in the context of a steganographic file system, to mitigate the risk of attacks initiated through analyzing data accesses from user applications. The first mechanism is intended to counter attempts to locate data through updates in between snapshots - in short, update analysis. The second mechanism prevents traffic analysis - identifying …

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Effects Of Query Complexity And Learning On Novice User Query Performance With Conceptual And Logical Database Interfaces, Keng Siau, Hock Chuan Chan, Kwok Kee Wei Mar 2004

Effects Of Query Complexity And Learning On Novice User Query Performance With Conceptual And Logical Database Interfaces, Keng Siau, Hock Chuan Chan, Kwok Kee Wei

Research Collection School Of Computing and Information Systems

Users see the database interface as the database system. A good interface enables them to formulate queries better. The semantics communicated through the interface can be classified according to abstraction levels, such as the conceptual and logical levels. With the conceptual interface, interaction is in terms of real-world concepts such as entities, objects and relationships. Current user-database interaction is mainly based on the logical interface, where interaction is in terms of abstract database concepts such as relations and joins. Many researchers argue that end users will perform better with the conceptual interface. This research tested this claim, as well as …

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Knowledge-Based Support In A Group Decision-Making Context: An Expert-Novice Comparison, Fiona Fui-Hoon Nah, I. Benbasat Mar 2004

Knowledge-Based Support In A Group Decision-Making Context: An Expert-Novice Comparison, Fiona Fui-Hoon Nah, I. Benbasat

Research Collection School Of Computing and Information Systems

This research examines the use of knowledge-based and explanation facilities to support group decision making of experts versus novices. Consistent with predictions from the persuasion literature, our results show that experts exhibit a higher level of criticality and involvement in their area of expertise; this not only decreases their likelihood of being persuaded by a knowledge-based system, but also accounts for a lower group consensus among experts as compared to novices. Novices are more easily persuaded by the system and find the system to be more useful than experts do. This research integrates theories from the persuasion literature to understand …

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Phoneme-Based Transliteration Of Foreign Names For Oov Problem, Wei Gao, Kam-Fai Wong, Wai Lam Mar 2004

Phoneme-Based Transliteration Of Foreign Names For Oov Problem, Wei Gao, Kam-Fai Wong, Wai Lam

Research Collection School Of Computing and Information Systems

A proper noun dictionary is never complete rendering name translation from English to Chinese ineffective. One way to solve this problem is not to rely on a dictionary alone but to adopt automatic translation according to pronunciation similarities, i.e. to map phonemes comprising an English name to the phonetic representations of the corresponding Chinese name. This process is called transliteration. We present a statistical transliteration method. An efficient algorithm for aligning phoneme chunks is described. Unlike rule-based approaches, our method is data-driven. Compared to source-channel based statistical approaches, we adopt a direct transliteration model, i.e. the direction of probabilistic estimation …

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Spatial Queries In The Presence Of Obstacles, Jun Zhang, Dimitris Papadias, Kyriakos Mouratidis, Manli Zhu Mar 2004

Spatial Queries In The Presence Of Obstacles, Jun Zhang, Dimitris Papadias, Kyriakos Mouratidis, Manli Zhu

Research Collection School Of Computing and Information Systems

Despite the existence of obstacles in many database applications, traditional spatial query processing utilizes the Euclidean distance metric assuming that points in space are directly reachable. In this paper, we study spatial queries in the presence of obstacles, where the obstructed distance between two points is defined as the length of the shortest path that connects them without crossing any obstacles. We propose efficient algorithms for the most important query types, namely, range search, nearest neighbors, e-distance joins and closest pairs, considering that both data objects and obstacles are indexed by R-trees. The effectiveness of the proposed solutions is verified …

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Group Nearest Neighbor Queries, Dimitris Papadias, Qiongmao Shen, Yufei Tao, Kyriakos Mouratidis Mar 2004

Group Nearest Neighbor Queries, Dimitris Papadias, Qiongmao Shen, Yufei Tao, Kyriakos Mouratidis

Research Collection School Of Computing and Information Systems

Given two sets of points P and Q, a group nearest neighbor (GNN) query retrieves the point(s) of P with the smallest sum of distances to all points in Q. Consider, for instance, three users at locations q1 , q2 and q3 that want to find a meeting point (e.g., a restaurant); the corresponding query returns the data point p that minimizes the sum of Euclidean distances |pqi| for 1 ≤i ≤3. Assuming that Q fits in memory and P is indexed by an R-tree, we propose several algorithms for finding the group nearest neighbors efficiently. As a second step, …

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Efficient Group Pattern Mining Using Data Summarization, Yida Wang, Ee Peng Lim, San-Yih Hwang Mar 2004

Efficient Group Pattern Mining Using Data Summarization, Yida Wang, Ee Peng Lim, San-Yih Hwang

Research Collection School Of Computing and Information Systems

In group pattern mining, we discover group patterns from a given user movement database based on their spatio-temporal distances. When both the number of users and the logging duration are large, group pattern mining algorithms become very inefficient. In this paper, we therefore propose a spherical location summarization method to reduce the overhead of mining valid 2-groups. In our experiments, we show that our group mining algorithm using summarized data may require much less execution time than that using non-summarized data.

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Evaluating The Usability Of A Group Support System Using Co-Discovery, Keng Siau Jan 2004

Evaluating The Usability Of A Group Support System Using Co-Discovery, Keng Siau

Research Collection School Of Computing and Information Systems

Group Support Systems (GSSs) have emerged as a new type of information system to aid group decision-making. With the proliferation of such systems in organizations, evaluation of GSSs is becoming increasingly important. This paper reports the evaluation of an existing GSS. Our usability framework consists of nine dimensions: visual clarity, consistency, compatibility, informative feedback, explicitness, flexibility and control, error prevention and correction, ease of learning, and ease of use. We make use of the co-discovery method where teams of two participants perform tasks together while being observed. The study involves questionnaires and interview sessions. The strengths and weaknesses of the …

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Supply Chains Integration: Architecture And Enabling Technologies, Keng Siau, Yuhong Tian Jan 2004

Supply Chains Integration: Architecture And Enabling Technologies, Keng Siau, Yuhong Tian

Research Collection School Of Computing and Information Systems

An effective and efficient supply chain is vital to the competitiveness and the survival of an organization. With the emergence of the e-business era, supply chain systems need to be able to extend beyond the traditional boundaries. This paper proposes integrated supply chain architecture (SCA) that combines the benefits of Enterprise Resource Planning (ERP) and the various supply chain applications. Some necessary criteria for an integrated supply chain include completeness, security, flexibility, scalability, and interoperability. The enabling technologies for such a supply chain system include XML, DCOM, CORBA, SOAP, Net, and Semantic Web. Wireless and mobile technologies could further extend …

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Java-Based Digital Library Portal For Geography Education, Zehua Liu, Hai Yuan, Ee Peng Lim, Ming Yin, Dion Hoe-Lian Goh, Yin-Leng Theng, Wee-Keong Ng Jan 2004

Java-Based Digital Library Portal For Geography Education, Zehua Liu, Hai Yuan, Ee Peng Lim, Ming Yin, Dion Hoe-Lian Goh, Yin-Leng Theng, Wee-Keong Ng

Research Collection School Of Computing and Information Systems

G-Portal is a Java-based digital library system for managing the metadata of geography related resources on the Web. In addition to providing a flexible repository subsystem to accommodate metadata of different formats using XML and XML Schemas, G-Portal organizes metadata into projects and layers, and supports an integrated and synchronized classification and map-based interfaces over the stored metadata. G-Portal also includes a classification subsystem that creates category structures and classifies metadata resources into categories based on user-specified classification schemas. Furthermore, G-Portal users can annotate resources and make their annotations available to others. In this paper, we describe the design and …

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Web Usage Mining: Algorithms And Results, Ee Peng Lim, Yew-Kwong Woon, Wee-Keong Ng Jan 2004

Web Usage Mining: Algorithms And Results, Ee Peng Lim, Yew-Kwong Woon, Wee-Keong Ng

Research Collection School Of Computing and Information Systems

No abstract provided.

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